Drug toxicities, patient compliance and limited penetrance into viral reservoirs (notably the central nervous system (CNS), gut and lymphatic organs) have diminished long-term antiretroviral therapy (ART) efficacy for HIV infection. Eliminating residual infection despite ART affected suppression of plasma viremia is our project goal. Novel strategies are sought for improved ART delivery to mononuclear phagocytes (MP: monocytes, perivascular and tissue macrophages and microglia) to bring drugs to tissue viral reservoirs. During the past R01 NS36126 funding cycle, now in its 17th year, we pioneered the development of long-acting injectable nanoformulated ART (nanoART) with superior biodistribution and pharmacokinetics over native drugs. Monthly nanoART injection, to subcellular sites of viral replication is possible We posit that this Trojan Horse MP carriage of the drug formulations can facilitate long-lived storage depots, in liver and spleen, resulting in reduced viral mutation and sustained plasma ART levels. Our drug formulations can readily cross the blood- brain barrier (BBB), from monocytes to endothelial cells, and enable drug transfer to and from an infected CNS. The current proposal seeks to perfect nanoART technology and as such move it to human use. First, we seek to maximize viral clearance (measured reduction of integrated viral DNA) by developing a range of antiretroviral nanoformulated drugs used alone or in combination. These include ritonavir boosted atazanavir, maraviroc, lamivudine, dolutegravir and efavirenz. Second, synthesis of polymer drug packaging with attachments of specific ligand coating will direct the drug to specific virus' target cells, tissues and subcellular regions to optimize antiretroviral activities. We posit that such cell-targeted nanoART will facilitate cell entry, intracellular trafficking and drug secretion. Third, we will probe the best directed formulations in rodents using a newly discovered small magnetite ART (SMART) platform. This will readily permit evaluation of broad numbers of coating ligands. Fourth, we will evaluate the functional consequences to the cell as it is linked to intracellular particle trafficking and stability. Fifth SMART formulations that pass evaluation will be synthesized by crystalline particles and evaluated for drug pharmacokinetics (uptake, release, plasma, and tissue distribution). This will include measures of BBB penetrance and tissue drug levels in brain, spleen, lymph nodes, and liver. Histologic and imaging assays will evaluate potential drug toxicities. Last, the most promising drug polymer formulations will be tested for antiretroviral efficacy, immune and neuroprotection in a humanized mouse model of HIV infection and neuroAIDS. The overall premise is to develop the necessary state of the art tools to improve nanoART induced viral reduction in its CNS and other viral reservoirs.